摘要
High-speed flows have consistently presented significant challenges to experimental research due to their complex and unsteady characteristics.This study investigates the use of the megahertz-frequency particle image velocimetry(MHz-PIV)technique to enhance time resolution under high-speed flow conditions.In our experiments,five high-speed cameras were utilized in rapid succession to capture images of the same measurement area,achieving ultra-high time resolution particle image data.Through advanced image processing techniques,we corrected optical distortions and identified common areas among the captured images.The implementation of a sliding average algorithm,along with spectral analysis of the compressible turbulent flow field based on velocity data,facilitated a comprehensive analysis.The results confirm the capability of MHz-PIV for high-frequency sampling,significantly reducing reliance on individual camera performance.This approach offers a refined measurement method with superior spatiotemporal resolution for high-speed flow experiments.
高速流动因其复杂且非定常的特性,一直是实验研究中的重要挑战.本文提出了一种适用于高速流动条件的高时间分辨率实验方法(MHz-PIV).通过5台高速相机交替拍摄相同测量区域,获取了超高时间分辨率的粒子图像数据.结合先进的图像处理技术,进行光学畸变校正,并提取了图像中的公共区域.随后,采用滑动平均算法计算速度场,并基于速度数据对可压缩湍流场进行了频谱分析,完成了功率谱密度的深入解析.研究结果表明,MHz-PIV技术能够在降低对单台相机性能依赖的情况下实现高频采样,为高速流动研究提供了一种兼具高时空分辨率的测量手段.
基金
supported by the National Key Research and Development Program of China(Grant No.2020YFA0405700).
